Data from 3 randomized clinical trials were pooled for this post-hoc analysis. After completing the double-blind portion, patients were eligible to enter the 1-year open-label extension (OLE), which began immediately after the maintenance period or after a 4-week taper period. ESL was initiated at 400 or 800 mg/day, titrated in 400mg increments to a maximum 1600 mg/day. HRQOL was measured at baseline and last assessment using the Quality of Life in Epilepsy Inventory (QOLIE-31). Mean QOLIE-31 scores and mean change in scores were analyzed (t-test). The percentage of patients with QOLIE-31 score improvements beyond the minimal important change (MIC) threshold (baseline to final assessment) is described.

Of 959 patients who entered, 677 patients completed the OLE. Mean change in seizure worry, overall quality of life, emotional well-being, medication side effects, social functioning, and total score were significantly improved for patients who entered the OLE. Mean change ranged from 0.76 (energy/fatigue) to 4.93 (seizure worry). Mean change in all QOLIE-31 categories was significantly improved in patients who completed the OLE, ranging from 2.16 (cognitive functioning) to 6.58 (seizure worry). The highest percentage of patients reached the MIC threshold in social functioning (46.8%-48.9%), followed by medication effects (43.8%-47.4%), and seizure worry (42.1%-45.3%) in patients who entered the OLE and who completed the OLE, respectively. The lowest number of subjects met MIC criteria for energy/fatigue in both patient groups.